如何将Android设备与3D打印机连接[重复]

当应用程序尝试在其主线程上执行联网操作时，将引发此异常。在

AsyncTask

class RetrieveFeedTask extends AsyncTask<String, Void, RSSFeed> {    private Exception exception;    protected RSSFeed doInBackground(String... urls) {        try { URL url = new URL(urls[0]); SAXParserFactory factory = SAXParserFactory.newInstance(); SAXParser parser = factory.newSAXParser(); XMLReader xmlreader = parser.getXMLReader(); RssHandler theRSSHandler = new RssHandler(); xmlreader.setContentHandler(theRSSHandler); InputSource is = new InputSource(url.openStream()); xmlreader.parse(is); return theRSSHandler.getFeed();        } catch (Exception e) { this.exception = e; return null;        } finally { is.close();        }    }    protected void onPostExecute(RSSFeed feed) {        // TODO: check this.exception        // TODO: do something with the feed    }}

如何执行任务：

在

MainActivity.java

oncreate()

new RetrieveFeedTask().execute(urlToRssFeed);

不要忘记将其添加到

AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET"/>